I had a tail stall in a 402 a couple of months ago. I of course had ice on the plane. I was experiencing a problem with ice ridging. The ice was actually building up on top of the boots and aft of any areas where the boots would inflate. The temp was -4 C and the windshield only had water flowing over it. I lost 30 knots groundspeed and about 35 indicated because of this. The yoke started moving forward and aft and then a sharp movement of it. The nose was porpoising a bit.
The proper procedure for recovery is to pull up and reduce power a little. Just the opposite of a wing stall. However, when I did that since I lost so much indicated airspeed and inflating the boots while recovering I experienced a minor wing stall. I was only indicating around 115 or 120kts. Could have been an accelerated stall or who knows. It definitely woke me up. I now respect ice more than I ever thought. I try my best to avoid ice at all costs. I either climb, descend, or do anything that I can to avoid a lot of ice buildup. If you are flying a plane with boots, in some cases don't blow them too early. I've done that and they become almost worthless. Also, do a static runup before takeoff with enough power to keep.